Magnetic transfer method and apparatus

ABSTRACT

A favorable magnetic transfer is performed on a perpendicular magnetic recording medium. A permanent magnet apparatus provided with two permanent magnets, each having a width extending the length of the radial direction of a discoid magnetic recording medium, is used as a transfer magnetic field generating means. A conjoined body formed of the perpendicular magnetic recording medium, which has been initially magnetized unidirectionally in the direction perpendicular to the track surface thereof, and two master mediums, disposed on respective surfaces of the slave medium, is inserted between the permanent magnets. A rotating means rotates the conjoined body, in the direction along the tracks of the slave medium, while a transfer magnetic field is applied to the conjoined body in the direction substantially opposite that in which the initial magnetization of the magnetic layer of magnetic recording medium has been performed, so as to perform the magnetic transfer.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates in general to a magnetic transfer methodof conjoining the magnetic layer of a magnetic transfer master medium,which has been formed in a pattern for transferring data to a magneticrecording medium, and the magnetic layer of a slave medium to form aconjoined body, and applying a transfer magnetic field to said conjoinedbody so as to magnetically transfer the data borne by the pattern of themagnetic layer of the master medium to the magnetic layer of the slavemedium.

2. Description of the Related Art

Generally speaking, with regard to magnetic storage mediums, there is ademand for increased storage capacity and low cost. Further desired areso-called high-speed access mediums, which are capable of advantageouslyreading out the data of a desired location in a short time. Examples ofthese mediums include the high density magnetic recording mediums(magnetic disk mediums) utilized in hard disk apparatuses and floppy (R)disk apparatuses. So-called tracking servo technology, wherein themagnetic head accurately scans a narrow width track to achieve a highS/N ratio, plays a substantial role in attaining the high storagecapacity thereof. A servo signal, address data signal, replay clocksignal, etc., used for tracking within a certain interval occurring inone rotation of the disk are “preformatted”, that is, recorded on thedisk in advance.

Magnetic transfer methods realizing accurate and efficientpreformatting, wherein the data such as a servo signal or the like borneon a master medium is magnetically transferred therefrom to a magneticrecording medium, have been proposed in, for example, JapaneseUnexamined Patent Publication Nos. 63(1988)-183623, 10(1998)-40544, and10(1998)-269566.

According to these magnetic transfer technologies, a master mediumhaving an uneven pattern corresponding to the data that is to betransferred to a slave medium (a magnetic recording medium) is prepared.By bringing this master medium brought into close contact with a slavemedium to form a conjoined body, and applying a transfer magnetic fieldthereto, a magnetic pattern corresponding to the data (e.g., a servosignal) borne on the master medium is transferred to the slave medium.The preformatting can be performed without changing the relativepositions of the master medium and the slave medium—that is, while thetwo media remain static. Therefore not only is it possible to perform anaccurate recording of the preformat data, it becomes possible toadvantageously do so in an extremely short time.

However, as to the magnetic recording medium, two possibilities arelongitudinal magnetic recording mediums provided with a goodmagnetization axis in the longitudinal direction in relation to thesurface of the magnetic layer thereof, and perpendicular magneticrecording mediums provided with an easy magnetization axis in theperpendicular direction in relation to the surface of the magnetic layerthereof; however, in current practice, longitudinal magnetic recordingmediums are generally employed, and the magnetic transfer technologydescribed above has also been developed focusing mainly on thelongitudinal magnetic recording mediums as the magnetic recording mediumof choice. On the other hand, if a perpendicular magnetic recordingmedium is employed, in comparison to the longitudinal magnetic recordingmediums, an increase in data storage capacity can be expected.

For cases in which a magnetic transfer is performed on a perpendicularmagnetic recording medium, a magnetic field must be applied in theperpendicular direction with respect to the surface of the magneticlayer thereof; wherein the optimal conditions differ with respect tocases in which a magnetic transfer is performed on a longitudinalmagnetic recording medium.

SUMMARY OF THE INVENTION

The present invention has been developed in view of the forgoingcircumstances, and it is an object of the present invention to provide amagnetic transfer master medium capable of performing a favorablemagnetic transfer onto a perpendicular magnetic recording medium.

The magnetic transfer method according to the present invention is amagnetic transfer method comprising the steps of: conjoining the databearing surface, which consists of a magnetic layer formed in a patterncorresponding to the data to be transferred to the magnetic layer of aslave medium, of a master medium with the magnetic layer of said slavemedium to form a conjoined body, and applying a transfer magnetic fieldto the respective magnetic layers of the conjoined master medium andslave medium to magnetically transfer the data to the slave medium,wherein

the slave medium is a perpendicular magnetic recording medium, and afterthe magnetic layer of said slave medium has been subjected to an initialmagnetization process consisting of applying an initial direct currentmagnetic field to said magnetic layer unidirectionally in the directionperpendicular to the track direction thereof to initially magnetize saidmagnetic layer, the magnetic layer of the slave medium and the magneticlayer of the master medium are conjoined and a transfer magnetic fieldis applied to the respective magnetic layers thereof in the directionopposite that in which the initial direct current magnetization has beenperformed.

Here, the expression “magnetically transfer the data” refers to theformation of a pattern, which corresponds to said data, on themagnetization array of the magnetic layer of the slave medium.

Further, the referents of “conjoined” include not only the state whereinthe respective surfaces of both of said mediums are in complete contactwith each other, but also states wherein said mediums are disposed in astate wherein a uniform interval is maintained between the respectivesurfaces thereof.

Still further, the initial magnetization of the slave medium can beperformed while the slave medium and the master medium are in theconjoined state, or while the slave medium and the master medium are notin the conjoined state. For the case in which the initial magnetizationis performed while the master medium and the slave medium are not in theconjoined state, the slave medium can be conjoined with the mastermedium after the initial magnetization thereof has been performed.

In addition, according to the magnetic transfer method of the presentinvention, the intensity of the transfer magnetic field is greater thanor equal to 0.5 times and less than or equal to 3.5 times the magneticcoercive force of the slave medium.

Further, the conjoined body formed of the conjoined master medium andslave medium can be moved relative to the transfer magnetic field, whichis generated over an area that is narrower than the track region, so asto pass the entirety of the track region of said slave medium throughthe transfer magnetic field.

In particular, for cases in which the slave medium is a discoid shapehaving concentric circular tracks, the aforementioned region narrowerthan the track region can be made to have a width spanning a singleregion extending in the radial direction of the track from the track ofthe smallest radius of the slave medium to the track of the largestradius of the slave medium; wherein the aforementioned relative movementcan consist of rotating the slave medium an amount corresponding to thecomplete track thereof.

Here, the track region of the slave medium and the concentric circulartracks refer to the track region formed by the magnetic transfer as wellas the concentric tracks.

Note that the movement relative to the transfer magnetic field may bemovement of the slave medium and the master medium, or, alternatively,movement of the transfer magnetic field.

The magnetic transfer method according to the present invention is amagnetic transfer method comprising the steps of: conjoining the databearing surface, which consists of a magnetic layer formed in a patterncorresponding to the data to be transferred to the magnetic layer of aslave medium, of a master medium with the magnetic layer of said slavemedium to form a conjoined body, and applying a transfer magnetic fieldto the respective magnetic layers of the conjoined master medium andslave medium to magnetically transfer the data to the slave medium, andcan be implemented by a magnetic transfer apparatus comprising:

an initial magnetizing means for subjected the slave medium to aninitial magnetization process consisting of applying an initial directcurrent magnetic field to said magnetic layer unidirectionally in adirection perpendicular to the track surface thereof to initiallymagnetize said magnetic layer unidirectionally in the directionperpendicular to said track surface, and

a transfer magnetic field applying means for applying a transfermagnetic field to the conjoined body formed of the conjoined mastermedium and slave medium in the direction opposite that in which theinitial direct current magnetization has been performed.

According to the magnetic transfer apparatus described above, thetransfer magnetic field applying means can be a means comprising: atransfer magnetic field generating means for generating a transfermagnetic field on a region of the slave medium narrower than the trackregion thereof, and a moving means for moving the conjoined body formedof the master medium and slave medium, which have their respectivemagnetic layers in close contact with each other, relative to saidtransfer magnetic field so as to pass the entirety of the track regionof said slave medium through the transfer magnetic field.

Further, the transfer magnetic field generating means can be a means forgenerating a transfer magnetic field over the region extending in theradial direction from the track of the smallest radius of a discoidslave medium to the track of the largest radius of said slave mediumhaving concentric circular tracks; wherein the moving means can be ameans for rotating the discoid slave medium a complete rotation alongthe tracks thereof.

Still further, for cases in which the slave medium is a discoidperpendicular recording medium having concentric circular tracks, afterthe magnetic layer of said slave medium has been subjected to an initialmagnetization process consisting of applying an initial direct currentmagnetic field to said magnetic layer unidirectionally in the directionperpendicular to the track direction thereof to initially magnetize saidmagnetic layer,

a transfer magnetic field can be generated across a region narrower thanthe track region of the slave medium and having a width larger than thatof the track of the largest radius, in the direction opposite that inwhich the initial direct current magnetization has been performed, toperform the magnetic transfer; wherein

the conjoined body formed of the conjoined slave medium and mastermedium can be moved relative to the transfer magnetic field so as topass the entirety of said track surface of the slave medium through saidtransfer magnetic field.

The magnetic transfer method according to the present invention is amagnetic transfer method comprising the steps of: conjoining the databearing surface, which consists of a magnetic layer formed in a patterncorresponding to the data to be transferred to the magnetic layer of aslave medium, of a master medium with the magnetic layer of said slavemedium to form a conjoined body, and applying a transfer magnetic fieldto the respective magnetic layers of the conjoined master medium andslave medium to magnetically transfer the data to the slave medium, andcan be implemented by a magnetic transfer apparatus comprising:

an initial magnetizing means for subjecting a discoid slave mediumhaving concentric circular tracks to an initial magnetization processconsisting of applying an initial direct current magnetic field to saidmagnetic layer unidirectionally in the direction perpendicular to thetrack surface thereof to initially magnetize said magnetic layerunidirectionally in the direction perpendicular to said track surface,and

a transfer magnetic field applying means for generating a transfermagnetic field across a region narrower than the track region of theslave medium and having a width larger than that of the track of thelargest radius, in the direction opposite that in which the initialdirect current magnetization has been performed, to perform the magnetictransfer; wherein

the conjoined body formed of the conjoined slave medium and mastermedium can be moved relative to the transfer magnetic field so as topass the entirety of said track surface of the slave medium through saidtransfer magnetic field.

Note that according to each magnetic transfer apparatus described above,the transfer magnetic field applying means may also serve as the initialmagnetizing means.

Further, as to the transfer magnetic field generating means for applyingthe transfer magnetic field, although an electromagnetic apparatus or apermanent magnetic apparatus can be employed thereas, from thestandpoint of the setting and adjustability of the intensity of themagnetic field and other such conditions, it is preferable that anelectromagnetic apparatus be employed. On the other hand, whenperforming a magnetic transfer at a fixed magnetic field intensity, fromthe standpoints of cost effectiveness and the ability to compactlyconfigure the apparatus, employing a permanent magnetic apparatus ispreferable.

According to the magnetic transfer method of the present invention:after subjecting the slave medium to an initial direct currentmagnetization unidirectionally in the direction perpendicular to thetrack surface thereof, by conjoining the magnetic layer of the slavemedium with the magnetic layer of a master medium to form a conjoinedbody, and applying a transfer magnetic field to said conjoined body inthe direction opposite that in which the initial direct currentmagnetization has been performed so as to perform a magnetic transfer, afavorable magnetic transfer can be performed on a perpendicular magneticrecording medium.

In particular, by making the intensity of the transfer magnetic fieldgreater than or equal to 0.5 times and less than or equal to 3.5 timesthe coercive force of the magnetic layer of the slave medium, themagnetic transfer can be performed more accurately.

Note that if the magnetic transfer is performed such that the conjoinedbody formed of the conjoined master medium and slave medium is movedrelative to the transfer magnetic field, which is generated over an areathat is narrower than the track region, so as to pass the entirety ofthe track region of said slave medium through said transfer magneticfield, the manufacture of preformatted slave mediums can be performedeasily and efficiently.

In particular, if the magnetic transfer is performed by use of a methodwherein the transfer magnetic field is generated over the region of adiscoid slave medium, which has concentric circular tracks, extending inthe radial direction from the track of the smallest radius thereof tothe track of the largest radius thereof, and the conjoined body formedof the conjoined master medium and slave medium is rotated so as toperform the magnetic transfer, the magnetic transfer to a disk shapedmagnetic recording medium or the like can be efficiently performed byuse of a simple apparatus configuration.

Further, if the magnetic transfer is performed by use of a methodwherein the transfer magnetic field is generated over the region of adiscoid slave medium narrower than the track region of the said slavemedium and having a width larger than that of the track of the largestradius, so as to perform the magnetic transfer; wherein the conjoinedbody formed of the conjoined slave medium and master medium is movedrelative to the transfer magnetic field so as to pass the entirety ofsaid track surface of the slave medium through said transfer magneticfield, because it becomes possible to perform the magnetic transferacross the entirety of the track surface by moving the conjoined bodylinearly, without any complicated rotational movement or the like, themagnetic transfer to a disk shaped magnetic recording medium or the likecan be performed efficiently and more easily.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a perspective view of the main part of a transfer magneticfield applying means implementing the magnetic transfer method accordingto the first embodiment of the present invention,

FIG. 2 is a perspective view of a master medium and a slave medium,

FIGS. 3A, 3B, and 3C are drawings illustrating the basic processes of amagnetic transfer method,

FIG. 4 is a schematic drawing of a variation on the first embodiment,

FIG. 5 is a perspective view of the main part of a transfer magneticfield applying means implementing the magnetic transfer method accordingto the second embodiment of the present invention, and

FIG. 6 is a schematic drawing of a variation on the second embodiment.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

Hereinafter the preferred embodiments of the present invention will beexplained with reference to the attached drawings. FIG. 1 is aperspective view of the main part of a transfer magnetic field applyingmeans implementing the magnetic transfer method according to the firstembodiment of the present invention.

The transfer magnetic field applying means 1 shown in FIG. 1 comprises apermanent magnet apparatus 5, which is a magnetic field generatingmeans, provided with two permanent magnets 5 a and 5 b, and a rotatingmeans (not shown) for rotating a conjoined body 10, which is formed ofthe a discoid slave medium 2 and two discoid master mediums 3, 4disposed on respective surfaces of the slave medium 2, in the directionindicated by the arrow A.

The permanent magnets 5 a and 5 b of the permanent magnet apparatus 5are each of a width that at least spans from the smallest radius trackr_(min) to the largest radius track r_(max) of the slave medium 2 shownin FIG. 2, and are disposed with the respective opposite magnetic polefaces thereof opposed so as to generate a magnetic field Hdu from thelower to the upper direction of the conjoined body 10. Further, becauseit is necessary that ample space be provided between the upper and lowerpermanent magnets 5 a, 5 b of the permanent magnet apparatus so as tofacilitate the unobstructed insertion and removal of the conjoined body10 therebetween, the permanent magnet apparatus is also provided with aseparating means (not shown) for mutually separating the permanentmagnets 5 a and 5 b. Note that the magnetic field Hdu is set so as to befrom 0.5 to 3.5 times the intensity of the coercive force Hcs of theslave medium.

FIG. 2 is an exploded view of a conjoined body 10. The conjoined body 10is formed of a slave medium 2, each respective magnetic layer 2 b, 2 cthereof with which the surface of the pattern of protrusion portions,which form a pattern on the respective master mediums 3 a and 4 a areconjoined; wherein, the radial direction of the respective surfaces ofthe slave medium 2 is matched with the width direction of the respectivepermanent magnet 5 a, 5 b when the slave medium 2 is set therebetween.

The slave medium utilized according to the magnetic transfer method ofthe present invention is a disk shaped magnetic recording medium such asa hard disk, a flexible disk, or the like, which has been provided witha magnetic recording layer on a single surface or on both surfacesthereof; in particular, a perpendicular magnetic recording medium onwhich an easily magnetizable direction of the magnetic recording layerhas been formed in the direction perpendicular to the recording surfacethereof is utilized thereas. The slave medium 2 shown in FIG. 2 is aperpendicular magnetic recording medium, which is recordable on bothsurfaces thereof, on which magnetic layers (magnetic recording layers) 2b, 2 c, are formed on both surfaces of the substrate 2 a thereof,respectively.

The master medium 3 is provided with protrusion portions formed in apattern corresponding to the data to be recorded onto the lowerrecording surface 2 b of the slave medium 2. The master medium 4 is ofthe same layered configuration as the master medium 3, and is providedwith protrusion portions formed in a pattern corresponding to the datato be recorded onto the upper recording surface 2 c of the slave medium2. The master mediums 3, 4 comprise a substrate 3 a, 4 a, respectively,on each of which a pattern of protrusion portions has been formed, and amagnetic layer 3 b, 4 b, formed on the surface of said substrate.

Next, the magnetic transfer method according to the present inventionwill be explained. First, with reference to FIGS. 3A, 3B, and 3C, thebasic processes of the magnetic transfer will be explained. FIG. 3Aillustrates the process wherein an initial magnetic field is appliedunidirectionally to the slave medium so as to perform the initialmagnetization thereof. FIG. 3B illustrates the process wherein the slavemedium and the master medium are conjoined to form a conjoined body, anda transfer magnetic field is applied thereto in the direction oppositethat in which the initial magnetization has been performed. FIG. 3Cshows the state of the recording surface of the slave medium after themagnetic transfer has been performed. Note that, FIG. 3 illustrates thelower face recording surface 2 d of the slave medium and the lowermaster medium 3, and an explanation has been given for only the magnetictransfer to said lower face recording surface 2 b; however, a magnetictransfer to the upper face recording surface 2 c can be performed in thesame manner.

As shown in FIG. 3A, an initial direct current magnetic field Hin isapplied in the direction perpendicular to the track surface of the ofthe slave medium 2 in advance, so as to initially magnetize therecording surface 2 b thereof in one direction. Then, as shown in FIG.3B, the surface of the recording layer 2 b of this slave medium 2 isconjoined with the pliable magnetic layer 3 b on the surface of theprotrusion portions of the master medium 3 to form a conjoined body, anda transfer magnetic field Hdu is applied thereto in the perpendicular tothe recording layer 2 b of the slave medium 2 and in opposite directionthat the initial direct current magnetic field Hin has been applied(i.e., in the direction opposite the direction in which the initialmagnetization has been performed) to perform the magnetic transfer. As aresult, the data (a servo signal, for example) corresponding to thepattern of protrusion portions formed on the surface of the mastermedium 3 is magnetically transferred and recorded on the magneticrecording surface 2 b of the slave medium 2, as shown in FIG. 3C.

Note that, even for cases in which the uneven pattern of the mastermedium 3 is a negative pattern, the opposite to that of the positivepattern shown in FIG. 3B, by reversing the above described directions inwhich the initial direct current magnetic field Hin and the transfermagnetic field Hdu are applied, the same data can be magneticallytransferred and recorded.

Next, the magnetic transfer method employing the transfer magnetic fieldapplying means shown in FIG. 1 will be explained.

First, the initial magnetization of the magnetic layers 2 b, 2 c of theslave medium 2 is performed by use of an initial direct currentmagnetizing means (not shown). That is to say, an initial direct currentmagnetic field Hin is applied to the magnetic layers 2 b, 2 c in thedirection perpendicular thereto, whereby the initial magnetization ofthe magnetic layers is performed.

Then, the pattern of protrusion portions on each of the master mediums3, 4 is conjoined to the magnetic layers 2 b, 2 c, respectively of theslave medium to form a conjoined body 10. Next, the conjoined body 10 isinserted between the permanent magnets 5 a, 5 b of the permanent magnetapparatus 5, wherein there is ample space separating said permanentmagnets 5 a, 5 b, so that the transfer magnetic field Hdu can be appliedthereto in the direction opposite that in which the initialmagnetization of the magnetic layers 2 b, 2 c of the slave medium hasbeen performed. Then, the permanent magnets 5 a, 5 b are made toapproach the respective surfaces of the conjoined body 10, and thetransfer magnetic field Hdu is applied. The conjoined body 10 is rotatedone full rotation in the direction indicated by the arrow A by arotating means (not shown) while the permanent magnets are in thevicinity of the conjoined body 10.

According to the current embodiment, the magnetic layers 2 b, 2 c of theslave medium have been initially magnetized in advance, and then themaster mediums 3, 4 have been conjoined therewith, respectively;however, the initial magnetization of the magnetic layers 2 b, 2 c ofthe slave medium 2 can be performed in the state wherein the slavemedium 2 has been conjoined with the master mediums 3, 4 in advance.

Further, according to the current embodiment, the conjoined body 10 hasbeen rotated relative to the transfer magnetic field Hdu; however, aconfiguration wherein the permanent magnets 5 a, 5 b are rotatedrelative to the conjoined body, which has been fixed in a stationaryposition, can also be employed.

According to the magnetic transfer apparatus of the present embodiment,a magnetic transfer to a perpendicular magnetic transfer medium can beperformed easily, and moreover, the quality of said transfer is high. Byenabling a favorable magnetic transfer to be performed to aperpendicular magnetic transfer medium, magnetic recording mediumshaving a larger storage capacity in comparison to conventionhigh-density planar recording mediums can be easily obtained.

Further, the transfer magnetic field applying means can be a meanscomprising a transfer magnetic field generating means, and a movingmeans; in particular, by making the transfer magnetic field generatingmeans a means for generating a transfer magnetic field over the regionextending in the radial direction from the track of the smallest radiusof a discoid slave medium to the track of the largest radius of saidslave medium having concentric circular tracks, and the moving means ameans for rotating the discoid slave medium relative to the transfermagnetic field a complete rotation along the track thereof, theperformance of a magnetic transfer to a discoid recording medium such asa hard disc or a flexible disk can be optimized, and the magnetictransfer can be performed efficiently by an apparatus of a simpleconfiguration.

Further, the transfer magnetic field applying means 1 can also be usedas the initial direct current magnetizing means. In this case, the upperand lower surfaces of the slave medium can be set between the permanentmagnets 5 a, 5 b so that the magnetic layers 2 b, 2 c thereof arereversed when the transfer magnetic field is to be applied, whereby thedirection in which the transfer magnetic field Hdu is applied thereto isthe opposite of that in which the initial direct current magnetic fieldHin was applied.

By combining the transfer magnetic field applying means and the initialdirect current magnetizing means into an integrated unit, the cost ofthe apparatus can be kept low, and it becomes possible to providepreformatted magnetic recording mediums at an inexpensive price.

Note that it is necessary that the value employed for the intensity ofthe transfer magnetic field and the initial direct current magneticfields be determined based on consideration of the coercive force of theslave medium, the relative permeability of the master medium and theslave medium, or the like. However, as described above, the intensity ofthe transfer magnetic field is to be a value greater than or equal to0.05 times and less or equal to than 3.5 times the coercive force Hcs ofthe slave medium.

According to the above-described embodiment, although a permanent magnetapparatus 5 has been employed for explanatory purposes as the magneticfield generating means, an electromagnetic apparatus 15 such as thatshown in FIG. 4 can also be employed thereas. The electromagneticapparatus 15 shown in FIG. 4 is disposed both above an below theconjoined body 10, and comprises a core 16, which is of a widthcorresponding to the length in the radial direction of the conjoinedbody, having a predetermined gap, and around which a coil 17 has beenwound. The magnetic transfer method employing this electromagneticapparatus 15 is substantially the same as that described above. If theelectromagnetic apparatus 15 is employed, it becomes possible to easilychange the direction and intensity of the magnetic field.

FIG. 5 is a perspective view of the main part of a transfer magneticfield applying means implementing the magnetic transfer method accordingto the second embodiment of the present invention.

According to the magnetic transfer method of the second embodiment,unlike the magnetic transfer method of the first embodiment, themagnetic disk or the magnetic field generating means is not rotated theone relative to the other; however, the magnetic transfer method of thesecond embodiment is a method wherein it is possible to perform themagnetic transfer across the entire track surface of the slave medium byonly a linear motion of the magnetic disk or the magnetic fieldgenerating means.

The transfer magnetic field applying means shown in FIG. 5 comprises apermanent magnet apparatus 105, which is a magnetic field generatingmeans, provided with two permanent magnets 105 a and 105 b, and a movingmeans (not shown) for moving the conjoined body 10, which is formed ofthe a discoid slave medium 2 and two discoid master mediums 3, 4disposed on respective surfaces of the slave medium 2, in the directionindicated by the arrow.

As shown in FIG. 2 the permanent magnets 105 a and 105 b of thepermanent magnet apparatus 105 are each of a width equivalent to thelength of the diameter d of the slave medium 2, and are disposed withthe respective opposite magnetic pole faces thereof opposed so as togenerate a magnetic field Hdu oriented from the lower to the upperdirection of the conjoined body 10. Note that the magnetic field Hdu isset so as to be from 0.5 to 3.5 times the intensity of the coerciveforce Hcs of the slave medium.

First, the initial magnetization of the magnetic layers 2 b, 2 c of theslave medium 2 is performed by use of an initial direct currentmagnetizing means (not shown). That is to say, an initial direct currentmagnetic field Hin is applied to the magnetic layers 2 b, 2 c in adirection perpendicular thereto, whereby the initial magnetization ofthe magnetic layers is performed.

Then, the surface of the pattern of protrusion portions, which form apattern on the surface of each of master mediums 3, 4 is conjoined tothe magnetic layers 2 b, 2 c, respectively, of the slave medium to forma conjoined body 10. Next, the conjoined body 10 is moved in thedirection indicated by the arrow and passed through the permanentmagnets 105 a, 105 b so that the transfer magnetic field Hdu is appliedto the entire surface thereof in the direction opposite that in whichthe initial magnetization of the magnetic layers 2 b, 2 c of the slavemedium has been performed.

According to the current embodiment, the magnetic layers 2 b, 2 c of theslave medium have been initially magnetized in advance, and then themaster mediums 3, 4 have been conjoined therewith, respectively;however, the initial magnetization of the magnetic layers 2 b, 2 c ofthe slave medium 2 can be performed in the state wherein the slavemedium 2 has been conjoined with the master mediums 3, 4 in advance.

According to the current embodiment, the conjoined body 10 has beenmoved relative to the transfer magnetic field Hdu; however, aconfiguration wherein the permanent magnets 5 a, 5 b can be movedrelative to the conjoined body, which has been fixed in a stationaryposition can also be adopted.

Further, according to the magnetic transfer apparatus of the currentembodiment, because the transfer magnetic field applying means comprisesa magnetic field generating means for generating a transfer magneticfield across a region smaller than the track region of the slave mediumand having a width larger than that of the track of the largest radius,and in the direction opposite that in which the initial direct currentmagnetization has been performed, it becomes possible to perform themagnetic transfer across the entirety of the track surface of the slavemedium by moving, by use of the moving means, the conjoined body formedof the conjoined slave medium and master medium through the transfermagnetic field in only a linear direction; whereby the moving means canbe of a simplified configuration.

Further, the transfer magnetic field applying means 1 can also be usedas the initial direct current magnetizing means. In this case, the upperand lower surfaces of the slave medium can be set between the permanentmagnets 5 a, 5 b so that the magnetic layers 2 b, 2 c thereof arereversed when the transfer magnetic field is to be applied, whereby thedirection in which the transfer magnetic field Hdu is applied thereto isthe opposite of that in which the initial direct current magnetic fieldHin was applied.

By combining the transfer magnetic field applying means and the initialdirect current magnetizing means into an integrated unit, the cost ofthe apparatus can be kept low, and it becomes possible to providepreformatted magnetic recording mediums at an inexpensive price.

Note that it is necessary that the value employed for the intensity ofthe transfer magnetic field and the initial direct current magneticfields be determined based on consideration of the coercive force of theslave medium, the relative permeability of the master medium and theslave medium, or the like. However, as described above, the intensity ofthe transfer magnetic field is to be a value greater than or equal to0.05 times and less or equal to than 3.5 times the coercive force Hcs ofthe slave medium.

According to the second embodiment, although a permanent magnetapparatus 105 has been employed for explanatory purposes as the magneticfield generating means, an electromagnetic apparatus 115 such as thatshown in FIG. 6 can also be employed thereas. The electromagneticapparatus 115 shown in FIG. 6 is disposed both above an below theconjoined body 10, and comprises two electromagnets, each formed of arespective core 16 a, 16 b, which is of width larger than the length ofthee radius of the largest track of the slave medium 2, around whichrespective coils 17 a, 17 b have been wound. The magnetic transfermethod employing this electromagnetic apparatus 15 is substantially thesame as that described above. If the electromagnetic apparatus 15 isemployed, it becomes possible to easily change the direction andintensity of the magnetic field.

Next a detailed explanation of the master medium and the slave mediumwill be provided.

As described above, the master medium 3 comprises a substrate 3 a havingprotrusion portions formed in a pattern on the surface thereof, and apliable magnetic layer 3 b formed on said surface (over the protrusionportions and the depression portions between the protrusion portions). Asynthetic resin, a ceramic material, an alloy, aluminum, glass, quartz,silicon, nickel, or the like is used to form the substrate 3 a of themaster medium 3. Further, as to the material forming the pliablemagnetic layer, Co, a Co alloy (CoNi, CoNiZr, CoNbTaZr, or the like),Fe, an Fe alloy (FeCo, FeCoNi, FeNiMo, FeAlSi, FeAl, FeTaN), Ni, a Nialloy (NiFe), or the like can be employed therefor; it is particularlypreferable that FeCo, or FeCoNi be employed. For cases in which thesubstrate 3 a is a ferromagnetic body formed of Ni or the like, althoughit is not necessary to provide the magnetic layer 3 b, the magnetictransfer can be improved if a magnetic layer 3 b is provided. If thesubstrate 3 a is formed of a non-magnetic body, it is necessary toprovide the magnetic layer 3 b.

The protrusion portions of the pattern on the data bearing surface ofthe master medium 3 can be formed by use of a stamping method, aphotolithography method, or the like. Hereinafter, a simple explanationof the method of manufacturing the master medium will be explained.

First, a layer of photoresist is formed on the smooth, flat surface of aglass substrate (or a quartz substrate) by use of a spin coatingprocess; then, a laser beam (or an electron beam), which is modulated incorrespondence to a servo signal, is emitted while this glass substrateis being rotated, and a predetermined pattern, such as that of a servosignal extending linearly in the radial direction from the rotationalcenter of each track, is exposed over the entire surface of thephotoresist on the portions corresponding to each frame on thecircumference. Then, the photoresist is subjected to a developmentprocess, the exposed portion of the photoresist is removed and anoriginal disk having an uneven pattern formed by the remainingphotoresist is obtained thereby. Next, the surface of the uneven patternthus formed on the surface of the original disk is subjected to aplating process (electroforming), whereby an Ni substrate having apositive uneven pattern is formed; said Ni substrate is then peeled awayfrom the original disk. This Ni substrate can be employed as a mastermedium as is, or after a pliable magnetic layer or a protective layerhas been further applied over the uneven pattern thereof, as required.

Further, the aforementioned original disk can be metal plated to form asecond original disk, and this second original disk used to perform afurther metal plating process, whereby a substrate having a negativeuneven pattern can be formed. Also, a third original disk can be formedby metal plating the second original disk or by hardening of a syntheticresin impressed onto the second original disk; this third original diskcan be metal plated to obtain a substrate having a positive unevenpattern.

On the other hand, after the uneven pattern has been formed ofphotoresist on the glass substrate, etching can be performed to formgrooves in the glass substrate, whereby a substrate from whichphotoresist has been removed can be obtained; a substrate can be formedtherefrom based on any of the methods described above.

Ni or a Ni alloy can be used as the material to form a metallicsubstrate, and any of various types of methods of forming a metalliclayer, including electroless deposition methods, electroformationmethods, spin coating methods, and ion plating methods can be employedas the plating method used to form this substrate. It is preferable thatthe height of the protrusions (the depth of the uneven pattern) formedon the substrate be in the range 50-800 nm; more preferably, in therange of 80-600 nm. For cases in which this uneven pattern is that of aservo signal, said pattern is formed long in the radial direction ofthereof. For example, it is preferable that the length in the radialdirection be 0.05-20 μm, and 0.05-5 μm in the circumferential direction;it is preferable that a pattern of this type, in which the length in theradial direction is long and within this range, is selected as thepattern for bearing servo signal data.

The magnetic layer 3 b, which is provided on the uneven pattern of thesubstrate, is formed of a magnetic material and by use of a vacuum layerforming means such as a vacuum deposition method, a sputtering method,an ion plating method, or by a metal plating method, etc. It ispreferable that the thickness of the magnetic layer 3 b be in the rangeof 50-500 nm; more preferably, in the range of 80-300 nm.

Note that it is preferable that a 5-30 nm Diamond Like Carbon (DLC) filmor other type of protective layer be formed over the pliable magneticlayer of the surface of the protrusion portions, and that a lubricatinglayer also be provided. Also, it is also possible to provide a contactenhancing layer formed of Si or the like between the pliable magneticlayer and the protective layer. The lubricant serves to improve thedurability with respect to surface damage due to friction or the likewhen correcting misalignments occurring during the conjoining process.

Note that according to the forgoing description, a master medium onwhich an uneven pattern has been formed on the surface thereof has beenexplained; however, a master medium having a flat surface formed byfilling in the depression portions of the uneven pattern formed thereonwith a magnetic layer can also be employed. In this case, the magneticlayer filling in the depression portions region can be a pattern formedin the same manner as a substrate having an uneven pattern.

The slave medium 2, as described above, is a disk shaped magneticrecording medium such as a hard disk, an HD flexible disk or the like;wherein the magnetic recording layer thereof is formed by coating alayer of magnetic material, or by forming a thin metallic magnetic filmrecording layer on the surface thereof. Note that here, a magnetic layeris provided with magnetic anisotropy and has an easy magnetization axisin the direction perpendicular to the track surface thereof. As to thematerial forming the thin metallic magnetic film recording layer, Co, aCo alloy (CoPtCr, CoCr, CoPtCrTa, CrNbTa, CoCeB, CoNi or the like), Fe,or an Fe alloy (FeCo, FeP, FeCoNi) can be employed therefor. Note thatit is preferable that a non-magnetic sub layer be provided so as toprovide the magnetic anisotropy required beneath the magnetic material(on the support body side thereof). A crystalline structure and alattice coefficient must be matched to the non-magnetic sub layer; tothis end, Cr, CrTi, CoCr, Crta, CrMo, NiAl, Ru, Pd or the like isemployed. Further, it is preferable that a backing layer for stabilizingthe state of the perpendicular magnetization of the magnetic layer, andimproving the recording and playback sensitivity be provided under thenon-magnetic sub layer.

Note that it is preferable that the thickness of the magnetic recordinglayer be greater than or equal to 10 nm and less than or equal to 500nm, and more preferably, greater than or equal to 20 nm and less than orequal to 200 nm. Further, it is preferable that the thickness of thenon-magnetic layer greater than or equal to 10 nm and less than or equalto 150 nm, and more preferably, greater than or equal to 20 nm and lessthan or equal to 80 nm. Still further, it is preferable that thethickness of the backing layer greater than or equal to 50 nm and lessthan or equal to 2000 nm, and more preferably, greater than or equal to80 nm and less than or equal to 400 nm.

1. A magnetic transfer method comprising the steps of: conjoining amagnetic layer, which has been formed in a pattern for transferring datato a magnetic layer of a slave medium, of a master medium with themagnetic layer of the slave medium to form a conjoined body, andapplying a transfer magnetic field to the respective magnetic layers ofthe conjoined master medium and slave medium to magnetically transferthe data to the magnetic layer of the slave medium, wherein said slavemedium is a perpendicular magnetic recording medium, and after themagnetic layer of said slave medium has been subjected to an initialmagnetization process comprising applying an initial direct currentmagnetic field to said magnetic layer unidirectionally in a directionperpendicular to a track direction thereof to initially magnetize saidmagnetic layer, the magnetic layer of said slave medium and the magneticlayer of the master medium are conjoined and a transfer magnetic fieldis applied to the respective magnetic layers thereof in a directionopposite that in which the initial direct current magnetization has beenperformed, and said conjoined body formed of the conjoined master mediumand slave medium is moved relative to the transfer magnetic field, whichis generated over a region that is narrower than a track region, so asto pass the entirety of the track region of said slave medium throughthe transfer magnetic field.
 2. A magnetic transfer method as defined inclaim 1, wherein an intensity of the transfer magnetic field is greaterthan or equal to 0.5 times and less than or equal to 3.5 times acoercive force of the magnetic layer of the slave medium.
 3. A magnetictransfer method as defined in claim 1, wherein the magnetic transfermaster medium comprises a substrate provided with a surface on which anuneven pattern corresponding to the data has been formed, and a magneticlayer formed on at least a surface of protrusion portions of saidsubstrate, whereby the magnetic layer of the master medium, which hasbeen formed in a pattern, is constructed by the magnetic layer formed onsaid surface of the protrusion portions.
 4. A magnetic transfer methodas defined in claim 1, wherein said data represent servo signals.
 5. Amagnetic transfer method as defined in claim 1, wherein said slavemedium is of a discoid shape having concentric circular tracks, and saidregion narrower than the track region has a width spanning a regionextending in the radial direction from a track of the smallest radius ofthe slave medium to a track of the largest radius of the slave medium,wherein the relative movement comprises rotating the conjoined bodyformed of the conjoined slave medium and master medium relative to thetransfer magnetic field along the track thereof.
 6. A magnetic transfermethod as defined in claim 1, wherein said slave medium is of a discoidshape having concentric circular tracks, and said region narrower thanthe track region has a width wider than the diameter of a track of thelargest radius of the slave medium, wherein the relative movementcomprises linearly moving the conjoined body formed of the conjoinedslave medium and master medium.
 7. A magnetic transfer apparatus forapplying a transfer magnetic field to a conjoined body formed of amagnetic transfer master medium having a magnetic layer formed in apattern for transferring data to a slave medium, and the slave mediumprovided with a magnetic layer, to magnetically transfer said data tothe magnetic layer of the slave medium, comprising: an initialmagnetizing means for subjecting the magnetic layer of the slave mediumto an initial magnetization process comprising applying an initialdirect current magnetic field to said magnetic layer unidirectionally ina direction perpendicular to a track surface thereof to initiallymagnetize said magnetic layer unidirectionally in the directionperpendicular to said track surface, and a transfer magnetic fieldapplying means for applying a transfer magnetic field to said conjoinedbody formed of the master medium and the slave medium in the directionopposite that in which the initial magnetization has been performed,wherein said transfer magnetic field applying means comprises, atransfer magnetic field generating means for generating a transfermagnetic field on a region of the slave medium narrower than the trackregion thereof, and a moving means for moving the conjoined body formedof the conjoined master medium and slave medium relative to saidtransfer magnetic field so as to pass the entirety of the track regionof said slave medium through the transfer magnetic field.
 8. A magnetictransfer apparatus as defined in claim 7, wherein the intensity of thetransfer magnetic field is greater than or equal to 0.5 times and lessthan or equal to 3.5 times a coercive force of the magnetic layer of theslave medium.
 9. A magnetic transfer apparatus as defined in claim 7,wherein the magnetic transfer master medium comprises, a substrateprovided with a surface on which an uneven pattern corresponding to thedata has been formed, and a magnetic layer formed on at least protrusionportions on the surface of said substrate, whereby said formed magneticlayer is formed by disposing the magnetic layer on the surface of saidprotrusion portions.
 10. A magnetic transfer apparatus as defined inclaim 7, wherein said data represent servo signals.
 11. A magnetictransfer apparatus as defined in claim 7, wherein the transfer magneticfield applying means also serves as the initial magnetizing means.
 12. Amagnetic transfer apparatus as defined in claim 7, wherein said magnetictransfer field generating means is an electromagnetic apparatus.
 13. Amagnetic transfer apparatus as defined in claim 7, wherein said magnetictransfer field generating means is a permanent magnet apparatus.
 14. Amagnetic transfer apparatus as defined in claim 7, wherein, the transfermagnetic field generating means is a means for generating a transfermagnetic field over a region extending in the radial direction from atrack of a smallest radius of a discoid slave medium to a track of alargest radius of said slave medium, which has concentric circulartracks, and said moving means is a means for rotating said conjoinedbody relative to the transfer magnetic field along said tracks.
 15. Amagnetic transfer apparatus as defined in claim 7, wherein, saidtransfer magnetic field generating means is a means for generating atransfer magnetic field across a region narrower than the track regionof the slave medium and having a width larger than the diameter of thetrack of the largest radius thereof, and said moving means is a meansfor moving said conjoined body in a linear direction relative to thetransfer magnetic field so as to pass the entirety of said track surfaceof the slave medium through said transfer magnetic field.